vein. The efferent vessels pass partly to the central and subclavicular groups of axillary glands and partly to the inferior deep cervical glands.

2. An anterior or pectoral group consists of four or five glands along the lower border of the Pectoralis minor, in relation with the lateral thoracic artery. Their afferents drain the skin and muscles of the anterior and lateral thoracic walls, and the central and lateral parts of the namma; their efferents pass partly to the central and partly to the subclavicular groups of axillary glands.

3. A posterior or subscapular group of six or seven glands is placed along the lower margin of the posterior wall of the axilla in the course of the subscapular artery. The afferents of this group drain the skin and muscles of the lower part of the back of the neck and of the posterior thoracic wall; their efferents pass to the central group of axillary glands.

4. A central or intermediate group of three or four large glands is imbedded in the adipose tissue near the base of the axilla. Its afferents are the efferent vessels of all the preceding groups of axillary glands; its efferents pass to the subclavicular group.

5. A medial or subclavicular group of six to twelve glands is situated partly posterior to the upper portion of the Pectoralis minor and partly above the upper border of this muscle. Its only direct territorial afferents are those which accompany the cephalic vein and one which drains the upper peripheral part of the mamma, but it receives the efferents of all the other axillary glands. The efferent vessels of the subclavicular group unite to form the subclavian trunk, which opens either directly into the junction of the internal jugular and subclavian veins or into the jugular lymphatic trunk; on the left side it may end in the thoracic duct. A few efferents from the subclavicular glands usually pass to the inferior deep cervical glands.

The Lymphatic Vessels of the Upper ExtremityThe lymphatic vessels of the upper extremity are divided into two sets, superficial and deep.

The superficial lymphatic vessels commence (Fig. 608) in the lymphatic plexus which everywhere pervades the skin; the meshes of the plexus are much finer in the palm and on the flexor aspect of the digits than elsewhere. The digital plexuses are drained by a pair of vessels which run on the sides of each digit, and incline backward to reach the dorsum of the hand. From the dense plexus of the palm, vessels pass in different directions, viz., upward toward the wrist, downward to join the digital vessels, medialward to join the vessels on the ulnar border of the hand, and lateralward to those on the thumb. Several vessels from the central part of the plexus unite to